This invention relates to an apparatus and method for producing packages of filaments, strands and the like.
More particularly, this invention is directed to an apparatus and method for producing packages having a plurality of bundles of continuous filaments so that the package has neat edges and facilitates the removal of the distinct bundles of filaments from the package.
In the manufacture of continuous filaments or strands, the packaging of these materials to facilitate the removal of the continuous materials for use in sundry processes is an important aspect in their manufacture. Generally, when continuous filaments or strands are produced they are wound onto a package, and the package of filaments or strands is used subsequently to produce various manufactured products. The filaments or strands must be easily movable from their packages to have an efficient operation in producing manufactured products, and this is particularly important for multistrand packages. In addition, a package of continuous filaments or strands containing a plurality of distinct filaments or distinct strands should have neat edges and not featheredges at the ends of the package. A feather-edge package is detrimental to removing the distinct filaments or strands for further processing, since this type of package contains groups of filaments or strands in which one filament or strand of an array is wrapped on a substantially larger or smaller diameter of the package than another filament or strand in the same array. When this type of package is unwound different lengths of the filaments or strands would be obtained. This difference in length is commonly referred to as catenaries. The catenaries can cause looping and snarling in the processing of the continuous filaments or strands from the package into manufactured products. Also the feather-edge type package presents a greater risk for damage occurring to the continuous filaments and/or strands at the edge of the package during shipment of the packages. Any damage to the continuous filaments or strands at the ends of the packages could result in broken filaments or strands engendering difficulties when the filaments are removed from the package. The feather-edge package usually has a larger diameter in the center of the package than the diameter at the ends of the package. An extreme uneveness in the diameter of the package requires the controlled use of additional devices in winding such a package so that the guide used to traverse the continuous filaments or strands onto the package continuously moves away from the building package. This movement prohibits the building package from touching the traversing guide.
In the manufacture of continuous glass fibers and/or strands, a roving can be produced, which is a cylindrically shaped package of one or more bundles of glass fibers wound in parallel. Traditionally, these roving packages have been produced by mounting a plurality of packages of glass fiber strands that were produced in forming the glass fiber strand on a creel or support and gathering the plurality of strands in a parallel array and winding these strands onto a cylindrical package.
Recently it has become a standard practice in the industry to produce a cylindrically shaped package of bundles of glass fibers during the formation of the glass fibers. This directly wound package has at least flat surfaces and at least nearly square edges on both ends of the packages. Such a directly wound cylindrical package of strand has the benefit of being made on a large scale in one operation, i.e. starting with the glass making raw materials and finishing with a cylindrical package sometimes referred to as a roving package that is ready for packaging and shipment.
Reportedly, a direct drawn roving package has been developed to take full advantage of even tensioning of glass fibers that are to be used in reinforcing polymeric materials. This is reported at pages 261 through 263 in "The Manufacturing Technology of Continuous Glass Fibers", by K. L. Lowenstein, Elsevior Scientific Publishing Company, Amsterdam, The Netherlands, 1973. In the production of roving packages, the lay of the strands in the successive layers making up the package is important to achieve the desired dimensions of the package. Also, the lay of the strands is important in roving packages in removing the strands from a roving package to use the strands for various applications, such as the formation of continuous strand mat, or the chopping of the strands to produce chopped glass fibers for reinforcement of polymeric and/or elastomeric materials, and/or the production of chopped strand mats. The ability to obtain the same number of distinct strands out of the wound roving package as were placed into the wound roving package during processing is an important parameter to the efficiency of further process operations. This ability is referred to as the splitting efficiency, which is defined in the book "The Manufacturing Technology of Continuous Glass Fibers" at pages 181 and 182 as the number of substrands formed expressed as a percentage of the number that should have been formed. The determination involves counting the number of substrands in a sample of known weight. The splitting efficiency can be found by the formula: NLT.div.10.sup.4 ws %. Where N is the number of substrands formed in a sample of a specific weight, L is the chopping length and T is the tex of the whole strand and w is the weight and s is the intended split of the strand.
It would be beneficial to both the producer and user of glass fiber strand to produce glass fiber strands in a multistrand, roving package produced directly in drawing the glass fibers, where the direct drawn roving packages have a good shape and a good split. To this end, the art has made numerous attempts to commercially produce a multiple strand, directly drawn roving product, but currently such a product is not readily available in the marketplace.
An early attempt discussed in U.S. Pat. No. 3,365,145 involves the use of a traversing device with a sensing means along with projections from the traversing device having pins which contact the edge of the layers of strands being wound so that the edge of the layer of a plurality of strands is forced into a straight edged package.
Another approach disclosed in U.S. Pat. No. 3,371,877 (Klink et al.) involves the use of a traversing device having a guide, which is a comb, wherein in each slot of the comb a single strand is located for placement of the strands in side-by-side array in the layer on the wound package. Above the comb on either end of the traverse are studs upon which the strand impinges at the end of each traverse to provide edge control in building up the successfully layered package. As is shown in the patent at FIG. 6, this edge control still allows the strands coming from the comb to remain in side-by-side relationship. Underneath the comb receiving the strands coming from the comb is a T-shaped slotted device acting as a sensor and guide member as the strands are wound in side-by-side relation onto the package.
A more recent approach is disclosed in U.S. Pat. No. 4,322,041 (Schullar et al.) which discloses the use of a traverse guide member which is used in very close proximity to the package of continuous multiple strand material being wound. The strand traverse guide is a vertical concave device with a V-shaped slot. The plurality of strands ride as separated strands on one or the other of the sloping sides of the V-shaped slot depending upon which direction the strand traversing guide is being traversed. The strand traversing guide also has a surface portion beneath the V-shape slot, which contacts all the strands and is in intimate contact with the rotating winder upon which the package is wound. This allows the strands to be wound on to the package almost immediately after contacting this surface portion of the guide.
It is an object of the present invention to provide an apparatus and method for producing a wound cylindrical package of a plurality of distinct filaments or distinct bundles of filaments, where the package has a neat appearance to reduce the risk of damage to the strands in the package during shipping, and, where the package has a good split efficiency in removing the distinct filaments or distinct bundles of filaments from the package for further processing.
It is a further object of the present invention to provide a traversing guide for linear filamentary material that is useful for various winding and traversing apparatus to produce a package of wound continuous filaments or strand having a reduced risk of damage to any of the strands in the package and having a good split efficiency with the distinct filaments or distinct strands in side-by-side relation to each other for the majority of the length of the successive layers in the package but having grouped relationship at the ends of the package.
It is another further object of the present invention to provide a package of wound filaments or strands having a plurality of distinct filaments or strands wound in successive layers, where the distinct filaments or distinct strands are in side-by-side relation to each other for the majority of the length of each layer, but exist in a grouped relation to each other at both ends of the cylindrical package to facilitate a neat package to reduce the risk of damage to any of the strands in the package during shipment and to allow for good split efficiency in removing the plurality of distinct filaments or distinct strands from the package for further processing.